Year	Percent
1991	21.619
1992	21.61
1993	22.218
1994	22.805
1995	23.379
1996	24.126
1997	24.738
1998	24.856
1999	25.369
2000	26.403
2001	26.726
2002	27.789
2003	27.68
2004	25.931
2005	22.409
2006	22.632
2007	22.081
2008	22.014
2009	20.379
2010	23.446
2011	25.882
2012	27.582
2013	22.725
2014	23.215
2015	23.824
2016	24.432
2017	25.609
2018	25.994
2019	26.412
2020	26.937
2021	27.54
2022	27.789